Cyclic oligopeptides of sarcosine (N-methylglycine)

Dale, Johannes; Titlestad, Kirsten

doi:10.1039/c29690000656

Cited by 62 publications

(33 citation statements)

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“…Like TBCN, cyclic peptides are also attractive candidates for artificial receptors because they have a rigid peptide backbone that forms a cavity and provides binding sites suitable for guest molecules. N ‐methylated cyclic triglicine has a C 3 symmetry conformation (crown form) elucidated by NMR30, 31 and X‐ray crystallography studies 32. Hioki et al33 reported the synthesis of N‐substituted cyclic triglycines using N , N ′, N ″‐triallyl‐cyclo‐triglicine as a scaffold.…”

Section: Introductionmentioning

confidence: 99%

Identification of a NCR⁺/NKG2D⁺/LFA‐1^low/CD94⁻ immature human NK cell subset

et al. 2009

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CD56bright natural killer (NK) cells, generated in vitro from CD34 1 hematopoietic progenitor cells, were characterized after a 30-day culture with flt3 ligand plus IL-15. Virtually, all CD56 bright cells expressed CD117, CD25, natural cytotoxicity receptors (NCRs), NKG2D, CD161, and CD244, while only a subset expressed CD18-CD11a (LFA-1), and CD94 molecule, defining an immature CD56 and activatory function that finely control their functional activities. In particular, they express inhibitory receptors for MHC class I (MHC-I) molecules, named killer cell immunoglobulin (Ig)-like receptors (KIRs) and C-type lectin CD94-CD159a, and many triggering molecules like NKp30, NKp44, NKp46, (called natural cytotoxicity receptors, NCRs), NKG2D, CD161, and CD244 (1-4). The majority of peripheral blood (PB) human NK cells are characterized by a phenotype with a low density expression of CD56 (CD56 dim ) and a high expression of CD16 (CD16 bright ), whereas a minority (approximately 5-10%) shows a bright expression of CD56 (CD56 bright ). This latter NK subset presents relatively high expression of some cytokine receptors (CD117 and CD25), lymph node homing receptors (CD62L and CCR7) and the CD94-CD159a heterodimeric inhibitory receptor. Moreover, differently from the well-known CD56 dim /CD16 bright cells, only a small percentage of the CD56 bright subset expresses KIR inhibitory receptors (5-10%) and CD16 dim (20-30%) while, in the majority, these antigens are not expressed (5). On the other hand, CD56bright NK cells are widely expressed in lymphoid tissues (6) and can be generated from CD34 1 cells when cultured with combinations of flt-3 ligand (FL) or stem cell factor plus IL-15 or IL-2 (7-10). During their development, NK cells sequentially acquire many different antigens and some of them allow to distinguish intermediate stages of NK cell differentiation. We had already taken advantage of CD161 antigen expression to define an immature CD161 1 /CD56 2 subset able to kill Jurkat cells via a TRAIL-dependent mechanism (3,11). When cultured with IL-12, this NK cell subset began to express CD56 molecule and became cytotoxic against K562 cells, thus suggesting a

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Section: Introductionmentioning

confidence: 99%

Identification of a NCR⁺/NKG2D⁺/LFA‐1^low/CD94⁻ immature human NK cell subset

et al. 2009

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“…cycZo(Sar)s has been reported to assume several different conformations in methanol. 21 The nmr pattern in methanol2' is also similar to those in water or MeZSO. If one considers the cis-trans isomerism of the Sar-Sar peptide bond, thirteen conformers are possible.…”

Section: Cycle( Sar)gmentioning

confidence: 63%

Studies on cyclic peptides. IV. Conformation of cyclo(Sar‐Sar‐Gly)₂, cyclo(Sar)₆ and cyclo(Sar‐Gly‐Gly)₂ and their conformational change induced by alkali thiocyanates

Sugihara¹,

Imanishi²,

Higashimura³

1976

Biopolymers

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SynopsisConformation of cyclo(Sar-Sar-Gly)z, cyclo(Sar)fi, and cyclo(Sar-Gly-Gly), was investigated by nmr spectroscopy. cyclo(Sar-Sar-Gly)z and cyclo(Sar)e, were shown to assume various conformations in dimethylsulfoxide. It was attributed to the distribution of cis as well as trans Gly-Sar or Sar-Sar amide links along the peptide backbone. In particular, cyclo(SarSar-Gly)Z took five or six different conformations: one or three Cz-symmetric conformations and four or three asymmetric conformations, respectively. Three of nine NH resonance signals were ascribed to the internally hydrogen-bonded glycine residues. cyclo(Sar-Sar-Gly)z and cyclo(Sar)6 showed a spectral change on the addition of alkali thiocyanates, indicating a conformational change induced by a complex formation with the alkali cations. The complex nmr spectrum due to a hybridization of different conformations changed with the salt addition into a simple nmr spectrum, suggesting a preponderence of a new, single conformation. On the basis of the spectral change, the strength for the cations binding the cyclic peptides was found to be in the order of K+ > Na+ > Rb+ > Cs+ for cyclo(Sar-Sar-Gly), and K+ > Rb+ > Cs+ for cyclo(Sar),j. On the other hand, cyclo(Sar-Gly-Gly)z in dimethylsulfoxide assumed a single Cz conformation having two glycyl peptide protons shielded from solvent and the other two exposed to solvent. This conformation did not change with the salt addition. Finally, the conformations of several cyclic peptides containing the sarcosine residue such as cyclo(Sar)c, cyclo(Sar-Sar-Gly)z, cyclo(Pro-Sar-Gly)z, and cyclo(Sar-Gly-Gly)n were compared. It appeared that proline and glycine residues reduced the conformational multiplicity of the cyclic peptide backbone, and the ability to bind alkali metal cations decreased in the above order.

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“…In order to establish conformational homogeneity of polypeptoids, one effective strategy is the inclusion of covalent macrocyclic constraints . After the first synthesis of cyclic PSar by Dale and Titlestad in 1969, crystallization structures of cyclic peptoids in bulk state had been reported in the early 1970s . Groth systematically examined the crystal structures of a series cyclopeptoids with ring numbers from 2 to 12 at high and low temperatures .…”

Section: Crystallization and Self‐assembly Of Polypeptoid Polymersmentioning

confidence: 99%

“…[74,75] After the first synthesis of cyclic PSar by Dale and Titlestad in 1969, crystallization structures of cyclic peptoids in bulk state had been reported in the early 1970s. [76] Groth systematically examined the crystal structures of a series cyclopeptoids with ring numbers from 2 to 12 at high and low temperatures. [77][78][79][80][81] With the development of methods for the synthesis of head-to-tail macrocycles, the crystallization, conformation and the reaction to metal ions of cyclic polypeptoids have been widely studied.…”

Section: Cyclic Polypeptoid Polymersmentioning

confidence: 99%

Recent advances in crystallization and self‐assembly of polypeptoid polymers

Zeng

Qiu

Wen

2019

Polymer Crystallization

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Poly(N‐substituted glycine)s, or polypeptoids, have attracted great interest from researchers due to their structural similarity to polypeptides. By taking advantage of relative ease of synthesis and good solubility in common solvents, polypeptoid polymers provide a versatile platform to generate peptide mimics with well‐defined chemical structures and architectures. As a class of peptidomimetic polymers, a deep understanding on the impact of side‐chain structures, main‐chain topologies, and backbone conformations with respect to the aggregation behaviors is the prerequisite for developing peptidomimetic polymers toward macromolecular and supramolecular engineering. This mini‐review highlights recent developments in the crystallization and self‐assembly of homopolymers, block copolymers, and macrocycles of polypeptoids.

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Cyclic oligopeptides of sarcosine (N-methylglycine)

Cited by 62 publications

References 0 publications

Identification of a NCR⁺/NKG2D⁺/LFA‐1^low/CD94⁻ immature human NK cell subset

Identification of a NCR⁺/NKG2D⁺/LFA‐1^low/CD94⁻ immature human NK cell subset

Studies on cyclic peptides. IV. Conformation of cyclo(Sar‐Sar‐Gly)₂, cyclo(Sar)₆ and cyclo(Sar‐Gly‐Gly)₂ and their conformational change induced by alkali thiocyanates

Recent advances in crystallization and self‐assembly of polypeptoid polymers

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Cyclic oligopeptides of sarcosine (N-methylglycine)

Cited by 62 publications

References 0 publications

Identification of a NCR+/NKG2D+/LFA‐1low/CD94− immature human NK cell subset

Identification of a NCR+/NKG2D+/LFA‐1low/CD94− immature human NK cell subset

Studies on cyclic peptides. IV. Conformation of cyclo(Sar‐Sar‐Gly)2, cyclo(Sar)6 and cyclo(Sar‐Gly‐Gly)2 and their conformational change induced by alkali thiocyanates

Recent advances in crystallization and self‐assembly of polypeptoid polymers

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Identification of a NCR⁺/NKG2D⁺/LFA‐1^low/CD94⁻ immature human NK cell subset

Identification of a NCR⁺/NKG2D⁺/LFA‐1^low/CD94⁻ immature human NK cell subset

Studies on cyclic peptides. IV. Conformation of cyclo(Sar‐Sar‐Gly)₂, cyclo(Sar)₆ and cyclo(Sar‐Gly‐Gly)₂ and their conformational change induced by alkali thiocyanates